HOMEBREW Digest #4846 Tue 13 September 2005

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  Re: Using chest freezer ("Michael O'Donnell")
  Chlorphenolics ("A.J deLange")
  Re: photodecomposition of beer (Jeff Renner)
  Re: Hops (Jeff Renner)
  photodecomposition of beer ("Peter A. Ensminger")
  Announcement: MHTG 2005 Franco-Belgian Challenge Cup (Eric Schoville)
  More on flasks ("Peed, John")
  Kunze and searching digests (Signalbox Brewery)
  Re: more esters, and also acids 1/2 ("Fredrik")
  Re: more esters, and also acids 2/2 ("Fredrik")

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---------------------------------------------------------------------- Date: Mon, 12 Sep 2005 22:13:37 -0700 From: "Michael O'Donnell" <mooseo at stanford.edu> Subject: Re: Using chest freezer Aaron wants to use a chest freezer cooled by a dorm fridge as a fermentation chamber: I was planning on doing this, but it turned out that the freezer getting thrown out at work merely had a cracked power cord (score!) so I used it for serving instead. What I did for a fermentation chamber was even more of a kluge than you propose and it worked fine. I built a box out of foam insulation with a hole in the side, took the door of the dorm fridge and duct-taped it into the hole. I built a box big enough for 4 corny kegs and it could keep it at 50 F if needed. With the better seal from a freezer, I suspect that it could lager. To keep it warm in the pansy winters we get in California (ooh, it's below 40, what do we do?) I bought a little de-humidifying heater... these are stick heaters of about 20 W... I like them because they just can't generate enough heat to ruin anything if the temp controller messes up. In Michigan, it would probably freeze solid. I would recommend that you get a little more creative with the temperature control, however... There will be a lot of cool air in the fridge when the temp control clicks off that will be wasted because the fans will go off at the same time... what would be sweet is 2 controllers, one for the fridge and one for the fans... or, maybe just put the fans on the controller and fill the fridge with bottles of cold water... let the fridge stay on all the time keeping the water cool and just blow air when the chest freezer gets to warm. The only problem I had with my arrangement was a lot of condensation from keeping it at 60-65... Since I only ran it for a few weeks at a time, I didn't worry about it, just put a bowl under the chill plate in the fridge. Your system will be much better sealed than mine was, and this problem will probably be less severe. Maybe put some de-humidifying crystals in there, or don't worry about it. As for which would be more efficient, define efficiency... in terms of saving electricity, yes, buying a new Energy-star fridge will be more efficient, but maybe not enough to worry about. I don't end up brewing as often as I like, so the fridge isn't really on that much. If you are talking about efficiency in construction, again, probably, but it sounds like a fun project and if you want efficiency, you could just buy beer. Let me know how it goes... my setup didn't survive my recent move, so I will need to recreate it... I'm thinking of doing exactly what you are proposing next time. cheers, mike Formerly, Monterey, CA, now Santa Barbara, CA Return to table of contents
Date: Tue, 13 Sep 2005 12:46:50 +0000 From: "A.J deLange" <ajdel at cox.net> Subject: Chlorphenolics The water is the most likely source. You can obtain simple, inexpensive test kits from aquarium supply stores or water testing suppliers (Lamotte, Hach) which will enable you to test your incoming water for the presence of chlorine and chloramine (be sure you get a kit which lets you measure both). An even simpler test is to draw a glass of water and let it stand over night. If it still smells of chlorine the next day that's a pretty good indicator than chloramination has been used. If you pour the water back and forth between two glasses and chlorine odor persists but goes away when a bit of crumbled Campden tablet is added that's also a pretty good indication that chloramine is in use. You can also call the water company and ask if they chloraminate. Given that you have chloramine the easiest way to get rid of it is to add a Campden tablet (crushed) to 20 gallons of tap water. This is usually sufficient but if it still smells of chlorine after treatment, add another half tablet. Keep doing this until the water doesn't smell of chlorine. If beer brewed with water treated thus is free of chorphenolics they you have found and solved your problem. RE decarbonation: Home ion exchange water softeners do strip out Ca and Mg and replace them with sodium. This is not generally regarded as a good thing to do to brewing water. Rule of thumb: hardness = good, alkalinity = bad. These softeners strip hardness and leave alkalinity untouched. Furthermore, it is more difficult to remove alkalinity after a trip through the softener because the stuff that precipitates the carbonate (Mg, Ca) must be put back in in the form of calcium (and/or magnesium) salts or lime. If the starting water had a lot of temporary hardness and you added enough calcium chloride to get most of the carbonate the water is going to be salty because the softener has added sodium equivalent to the bicarbonate and you've matched it with an equivalent amount of chloride. So skip the softener and decarbonate with lime or by boiling. Some calcium supplementation to augment carbonate and later (in the beer) oxalate precipitation is fine. As for the hose: go to an RV supply store or ships chandlery and buy one of the hoses they sell for shore water hookup. These are flavor neutral. Return to table of contents
Date: Tue, 13 Sep 2005 09:27:54 -0400 From: Jeff Renner <jsrenner at umich.edu> Subject: Re: photodecomposition of beer "Peter A. Ensminger" <ensmingr at twcny.rr.com> wrote from Syracuse, NY: > A recent review article ... discusses recent research on the > mechanism of > the flavin-mediated light-struck reaction, which leads to formation of > 'skunky' mercaptans following exposure of beer to blue light. Thanks, Peter. I understood the introduction and conclusion. The parts in the middle? One passing assertion jumped out at me because I had never heard the claim, and it is not attributed, despite ample footnotes throughout most of the article: > Moreover, health-beneficial properties due to particular compounds > present in hops confer to beer a unique position in the > appreciation of (low-)alcoholic drinks. Now, as much as I'd like to believe this, I'd like to have some substantiation. All I've ever heard is that hops can make you sleepy, but I haven't seen any scientific investigation into this. A quick google of health benefits of hops turns up only anecdotal herbalist kinds of claims of hops relaxing or sleep-inducing qualities - again, nothing I'd want to include in a scientific paper. Anyone know more about this assertion of "health-beneficial properties" of hops? Jeff - --- Jeff Renner in Ann Arbor, Michigan USA, jsrennerATumichDOTedu "One never knows, do one?" Fats Waller, American Musician, 1904-1943 Calculate your Rennerian Coordinates at http://hbd.org/ rennerian_table.shtml Return to table of contents
Date: Tue, 13 Sep 2005 09:34:34 -0400 From: Jeff Renner <jsrenner at umich.edu> Subject: Re: Hops Bill Frazier <billfrazier at worldnet.att.net> writes from Olathe, Kansas USA : > I've spotted some wild hops growing near my house. When are hops > ready to > pick? What are signs of hop flower maturity? Thanks. It's likely too late, at least based on hops here in SE Michigan, where the season is probably a little later than Kansas. They are ready when they are somewhat dry and papery feeling but still green. IIf they crumble when you squeeze them, they are perhaps too dry. They shouldn't be brown at all. The next question you are probably asking is, "What kind are they?" Ralph Olsen of HopUnion has told me that in (nearly?) all of the cases in which they have identified wild hops sent into them, they have turned out to be some variety of Cluster. I don't know if this is because they are escapees or if the indigenous hops or N.A. are that close to Cluster. Jeff - --- Jeff Renner in Ann Arbor, Michigan USA, jsrennerATumichDOTedu "One never knows, do one?" Fats Waller, American Musician, 1904-1943 Calculate your Rennerian Coordinates at http://hbd.org/ rennerian_table.shtml Return to table of contents
Date: Tue, 13 Sep 2005 10:53:29 -0400 From: "Peter A. Ensminger" <ensmingr at twcny.rr.com> Subject: photodecomposition of beer Regarding the statement, "... health-beneficial properties due to particular compounds present in hops confer to beer a unique position in the appreciation of (low-)alcoholic drinks" in the recent Huvaere & Keukeleire paper (see: <http://www.hbd.org/hbd/archive/4845.html#4845-1>) I would guess this is a 'throw-away' line. However, there has been extensive study of the effects/benefits of xanthohumol (a prenylated chalcone present in hops). Do a search for xanthohumol in PubMed: <http://www.ncbi.nlm.nih.gov/entrez/query.fcgi>. Numerous preclinical studies demonstrate anti-tumor/chemopreventative action and several other potentially beneficial effects. This may be because xanthohumol acts as a potent anti-oxidant. I could not find any clinical studies on hops or xanthohumol. Nevertheless, I'm still waiting for my doctor to say, "take two beers and call me in the morning" Cheerio! Peter A. Ensminger Syracuse, NY Beer data: http://hbd.org/ensmingr/ Return to table of contents
Date: Tue, 13 Sep 2005 10:58:48 -0500 From: Eric Schoville <eric at schoville.com> Subject: Announcement: MHTG 2005 Franco-Belgian Challenge Cup The Madison Homebrewers and Tasters Guild are pleased to announce the 2005 Franco-Belgian Challenge Cup. The contest is an attempt to encourage the homebrewing of French- and Belgian-style beers. As such, only French- and Belgian-style beers (BJCP Categorys 16-18) will be judged. The competition is sanctioned by the AHA and BJCP. AHA/BJCP 2004 Style Guidelines will be used. The contest will be held on 11/5/05. Additional information is available at our website: http://www.mhtg.org/contests/MHTG%20Contests.html Return to table of contents
Date: Tue, 13 Sep 2005 11:39:45 -0700 From: "Peed, John" <jpeed at elotouch.com> Subject: More on flasks John Shnupp comments on starters in Erlenmeyer flasks. While I agree that they're prone to boil-overs and foam-overs, the beauty of doing it all in the flask is that you minimize equipment, transfers and general handling. I boil on a gas stove, so hadn't thought about the perils of electric stove eyes. In general, you want to boil slowly and carefully. Likewise, you're pushing it if you try to decant and then juice the starter a second time - active yeasts like 1056 will usually foam right out the top. It might be best not to decant and re-juice - there's a lot to be said for keeping the system sealed and undisturbed until it's time to pitch. As for the foam stoppers, the seller claims that they will filter any contaminants/bacteria/yeast, and I have found this to be true; I've been making starters with foam stoppers on a stir plate for a while now and they come out clean. One thing that does not seem OK to me is to splash or otherwise introduce unfiltered air into starters or wort. The foam stoppers appear to work as advertised. After each use, wash sanitize in iodophor, then wring out the excess. As for cooling, I have always put the flask in a sink of cold tap water filled to the depth of the wort. After a few minutes the now warm water is replaced with ice water. Works fine, although I wouldn't push it by putting it in the freezer. I know that borosilicate glass is not completely immune to temperature shock because I shattered a hot quart measuring bowl once by setting it on a cold stainless countertop, but the lab glass stuff is high quality and should tolerate such things. What it won't tolerate very well is bumping, dropping and that sort of thing, as I've proven way too many times ... Again, the advantages of this starter "system" are: boil, cool, and fermentation all take place in one container, with no transfers; the container can breath while still protecting the contents; the stirring action pulls filtered air into the starter, reducing the time required while at the same time stimulating more yeast growth (most people agree that you get about twice as much yeast this way). John Peed Oak Ridge, TN Return to table of contents
Date: Tue, 13 Sep 2005 21:30:32 +0100 From: Signalbox Brewery <signalbox.brewery at ntlworld.com> Subject: Kunze and searching digests Two questions: There used to be a certain enthusiasm for Kunze's Technology Brewing and Malting round these parts. I haven't seen any mention for a while and yet there seems to be a new edition out "3rd completely updated english edition of "Technologie Brauer und Maelzer" - Published November 2004" according to the VLB's website. Are folk as fond of the new edition? Secondly I did try to answer the question through the hbd search page http://hbd.org/cgi-bin/hbdindex.cgi/hbd_index However I can't get this to return anything using either Mozilla Firefox or IE6. Any tips? David Edge Return to table of contents
Date: Tue, 13 Sep 2005 22:32:37 +0200 From: "Fredrik" <carlsbergerensis at hotmail.com> Subject: Re: more esters, and also acids 1/2 Dang, this formatting and 8k limit again. not sure if this gets readable. - --- The ester discussions are interesting. I really don't have much to add, and I kind of agree with what has been said that insisting on finding simple answers to complicated questions makes it even harder, if not impossible. But I can't resist throwing out some more ideas to feed the discussion. I apologize if it's foggy. I think there are possibly many ways to attach this, but I personally like to think this a bit like this from a modelling point of view: - I picture the cell as collection of pools. Each compound in a certain cell department is represented by a pool, and clearly each pool has a level. - All pools are cross-connected via a huge number of pathways. Each pathway has a well defined impact on the other pools as determined by the stochiometry. - But the specific rate of each pathways is part of the biological regulations. The rates depends on the type of reaction kinetics, but ideally reactant and product pools as per som standard mechanisms, as well as some enzyme pool and enzyme regulations. So given that we assume simplified standard kinetics, it boils down to enzyme regulations and enzyme pools - for each pathway. So far - it would be a matter or mapping out the pathways and pools, and implementing the necessary numerical routines to find the pool dynamics. But, the point where I find it gets almost overly hairy (supposing the computational problem wasn't hairy enough) is that how are these enzyme levels and acitivites regulated? Where are the rules for that?? Here it becomes evident that there is a living organism behind all this. So understanding how these enyzymes are regulated seems to require understanding the organism needs on a system level rather than molecular level? So to me, the practical question is not what molecular mechanisms yeast uses to pull off the regulatory task, it's why (ie. to maximize survival, and reproduction etc). How, would probaly get us down to details where I for one would get totally lost. So instead of asking how, I only want to know why, and hopefully use it as as shortcut. As I posted about before I started this fun but never ending project of a fermentation simulation a couple of years ago, and the while I think some progress is made, the closer I think I get the more do I realize that it's not good enough, and I keep revising the strategy without moving much forward. I have found no other way out but to adapt some of the nice approaches used in some of the simualtions that has been done. It leaves a set of pools, set of pathways, and for each pathway a set of parameters. Parameters that the organisms tweaks/expresses in order to attain their goals of life, and I don't even want to know How it's done. I just trust that after billions of years, it's figured it out. It's like the game of life, put in the rules, sit back and watch. Now the brute force way of finding the regulation output, given the goals (next problem), would probably require more computing power than the rest of the simulation. So right now, I'm hoping to find a clever way to do the task with less computing power. This is where I'm stuck fiddling atm. This turns out to be a very realistic problem since you never have infinite computing power in reality. I decided for myself that it can't be made much simpler than this, at least not in the general case? > 1. I think pitching rate affects total growth ONLY because of the > small amount of energy required for (non-growth-related) background > maintenance of the cells. Posts (I recall some by Steve) in the > archives suggest that this is a pretty small amount of energy and hence > total growth should not change dramatically with pitching rate. But if > there is a pool of Acetyl CoA laying around after growth stops, and AAT I'm a little doubtful on this. No doubt there is maintenance, and more cells => more maintenance. But I would also expect, that the specific(cellwise) maintenance per cell would increase significantly as the health drops. Low pitching rate, low aeration and I would suspect that the cellwise total maintenance cost to be higher than that of a more healthy cell? I would love to see data on this though. I haven't found that much, so I have missed something interesting. I know I have seen once a test indicating that more yeast -> less total biomass growth, but that was carried out by pitchting rates that I'd consider to be overpitching and lots of details was missing, also the difference was not that big. I suspect that if you add the order of a yeast cake then the story is probably different than if you compare 0.13 vs 1 million/ml/P? A big crappy yeast cake would probably require more *initial* maintenance though? /Fredrik Return to table of contents
Date: Tue, 13 Sep 2005 22:32:40 +0200 From: "Fredrik" <carlsbergerensis at hotmail.com> Subject: Re: more esters, and also acids 2/2 > 2. IS there a pool of Acetyl CoA lying around after growth stops? Growth doesn't *stop* completely until it's time to go dormant, but it slows down But when there is still growth, but the limiting factor limits the consumption of acetyl-CoA (like Steve wrote in the other response), the steady-state pool of acetyl-CoA increases. At some point the production got to be downregulated a bit because if the production is higher than consumption it wouldn't only pool, the poole level would just keep increasing, and that makes no sense. It also makes no sense to keep bleeding at full speed? But from the "downregulate" command to realisation there is probably a temporary excess pool level levels that has to bleeded off by other pathways. But even after this temporary pool-peak, the pool level will probabably reach a steady state value that is alot higher than during high growth, so there will be bleeding still. One question is, how fast the atf enzymes can arrive from the point where they're requested? would they risk miss the first peak or not? ie. would the atf enzyme level be higher after the peak than before? Depending on enzyme timings and their deactivaton rates, Perhaps a way to increase esters, might be to have the growth conditions "oscillate" from the early parts, in order have the "downs" stimulate enzyme synthesis and catch the coming acetyl-CoA peaks better? And I'd just guess that the enzymes downregulate slower than they upregulate? Just an idea. Not sure what would be the best wat to do that though but it sounds like a fun experiment. With really high pitching rates, the growth would keep the acetyl-CoA pool low for a a dominating part of relative consumption, and the population would probably consume less sugar while in the "high acetyl-CoA pool state", and thus the potential for ester synthesis lower? and once the drop finally comes, it's pretty much over. With a lower pitching rate, or poor aeration the consumption of acetyl-CoA due to growth would proabably drop much earlier probably due to low quality membranes, relative to the % of total sugar consumed. John Palmers idea sounds like the triggering condition for enzyme synthesis among other tings is the acetyl-CoA level which is plausible. If I am not mistaken I think I ready somewhere that specific atf enzymes are also induced by precense of fuesels too. So I still wonder exactly what regulates the enzyme levels. I assume the reason for the ester synthesis overall is a kind of regulation, and it would seem logical to alert this response system when the need for regulation becomes apparent(the signal), but not sooner? Can we even understand yeast by common sense logic? It's a pity Freud and Jung wasn't brewers or I'm sure they would have explained the yeast response patterns ;-) > 3. Do fatty acids ever leave the cell walls and if so what is their fate? The "activated" fatty acids (acyl-CoA) themselves hardly leave the cell. The fact that pH drops from ~5 to ~4 during fementation is becuase of organic acids beeing thrown out of the cell though. Excess acids in the cytosol is stressful so the yeast should try to throw them out to maintain cytosolic pH. Weak acids do more harm inside the cell, than outside, since once inside they protolyze completely and act as strong acids. But to an extent they probably leak back in again. Probably wasting lots of energy? But as it seems most of these acids, except acetic acid are probably TCA cycle intermediates? I don't know what extent acyl-CoA can bleeds off as acids? The only tioester hydrolases I've seen in the genome database is a peroxisome enzyme that splits the acyl-CoA into acid and CoASH. But it's reported to be relate play a roll only in fatty acid oxidation? Most organic acid analysis I've read about of beer seems to indicate that the major acids found in the beer are acetic acid + the TCA intermediates, like citric acid, succinic, malic etc, but in some analysis there also seem to exist a small amount of short chain fatty acids, like propionic and byturic. But I don't know if it's from yeast or bacteria. It is an interesting question - what would happen with the acetyl-CoA in yeast lacking of all alcohol acetyltransferase genes? Would they be overly stressed and drop significantly on high acyl-CoA pools and recover more slowly from oscillations in growth conditions? > 4. More practically--can I increase the iso-amyl acetate in my beer, without increasing (and in fact reducing) isoamyl alcohol levels, by simply adding acetic acid to the wort? I assume not, because how would it get into the yeast cells and how would it get transformed to Acetyl-CoA... but who knows? >From what I understand acetic acid acids can get into the cytosol from wort, and during *aerobic* conditions it could even convert to acetyl-CoA. But that said, I think that's not a way to increase the iso-amyl acetate anyway.. Maybe if we can fool the yeast to make the relevant enzymes to a larger extent. What if we add a high dose of iso-amyl alcohol or leucine in the starter? could that increase expression of the banana enzyme? But how fast would they deactivate once the need goes away? Maybe ester synthesis beeing a regulation mechanism that works "a bit wasteful" by bleeding off excess pools, that complements the other existing regulation mechanisms. Possibly useful for effiency in oscillating conditions? /Fredrik Return to table of contents
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